During the use of a complex patient treatment apparatus or surgical system, for example, surgical equipment used when performing ophthalmic surgery, the control of a variety of different subsystems, such as pneumatic and electronically driven subsystems may be required. Typically, the operation of the subsystems is controlled by a microprocessor-driven console. The microprocessor controls within a surgical console receive mechanical inputs from either the operator of the surgical system or from an assistant. A control input device, such as a footswitch, is often used to accept mechanical inputs. These mechanical inputs originate from the movement of the foot of an operator to govern the operation of a subsystem within the patient treatment apparatus. The mechanical inputs from the movement of the foot of the operator are translated into electrical signals which are fed to the microprocessor controls. The electrical signals are then used to control the operational characteristics of a subsystem in a complex patient treatment apparatus.
Examples of footswitches include a foot pedal or tiltable treadle similar to the accelerator pedal used to govern the speed of an automobile. The movement of the foot pedal or tiltable treadle typically provides a linear control input. Such linear control inputs may be used, for example, for regulating vacuum, rotational speed, power, or reciprocal motion.
In more complex footswitch assemblies, side or wing switches may be added to housings on either side of the foot pedal in order to provide additional capabilities to the footswitch. The condition of these side or wing switches is changed by the application of pressure from the front portion of the operator's foot or from the rear portion of the operator's foot.
As these footswitches became more complex, the need to establish secure reliable communications between the footswitch and the surgical console resulted in a number of wired pathways that connect the footswitch and surgical console. As the footswitches are moved about the operating room, these tethers, wires and cables can become tangled with other equipment. Accidentally disconnecting these cables can result in improper control inputs that have the potential to injure a patient. To address these problems, U.S. Pat. No. 7,781,941, issued 24 Aug. 2010, disclosed a surgical footswitch that includes a base, a pedal, a capacitance-sensing controller circuit, a wireless interface, and an internal power generator. In this footswitch, the pedal mounts upon the base and pivots, and is coupled to the capacitance-sensing controller circuit. As the pedal pivots, the capacitance-sensing controller circuit translates the mechanical signal of the pedal into a control signal based on the pedals position and/or orientation. The wireless interface is coupled to the capacitance-sensing controller circuit to receive the control signal, and then couples the surgical footswitch to a surgical console operable to control and direct surgical equipment. This wireless interface eliminates the tangle of wires or tethers, which may be a hazard in the surgical theater. The internal power generator translates footswitch movement into stored energy to eliminate potential failures of the footswitch during a procedure and reduce the need to replace batteries within the footswitch.
Even with these improved footswitches, however, there remains a need for improved performance and, in particular, for extended battery life.